Means for truing wheels for grinding formed cutters.



"I H JII I H W W.

Patented Au 14, 1917.

AWN! q M M! HIM I WWWWWW]! w. o. BARNES. MEANS FQRTRUIN GWHEELS FOR GRINDING FORMED CUTTERS. APPLICATION FILED JUNE?! 1916.

EN h HM ii? HI. 'lmH INVENTOH BY WW ATTORNEY UNITED STATES WILLIAM o. BARNES, or'fnoivfinsrnn, MASSACHUSETTS.

MEANS FOR TRUING WHEELS FOR G'ZRINDINQ'G FORMED CUTTEBS.

Specification of Letters Iatent.

PatentedvAug. 14, 1917.

Original application filed October 11, 1915, Serial No. 55,197. Divided and this application filed. June 27,

1916. Seria1No.106,143. I

To all whom it may concern:

Be it known that I, WILLIAM O. BARNES,

a citizen of the United States, resid ing "at Leominster, county of Worcester, State of Massachusetts, have invented an Improvement in Means for Truing Wheels for Grinding Formed Cutters, of which the following is a specification.

This application is a division of my application for patent for machine for grinding formed cutters, Serial No. 55,197, filed October 11, 1915, which matured into Patent No. 1,196,420, dated August 29, 1916, and

has for its object to provide means for truing the grinding wheels.

With this end in view, I have devised the novel mechanism which I will now describe, referring to the accompanying drawing forming a part of this specification and using reference characters to indicate the several parts.

, Figure 1 is a side elevation of the grinding I The spindle head is adjusted to therequired' position for use by means of a screw 24-carrying a hand wheel 25 which is provided with peripheral gage-marks 26 adapted to register with a pointer 27 carried by the spindle head. 28 denotes the spindle which is mounted in a bearing upon the head, 31 a grinding wheel carried by the spindle, 32 a rest for the cutter teeth in grinding, 33 a rough wheel truing pin, and 80 a contact member having a guide surface 34 for a templet, not shown, and a guide surface 35 for the wheel truing device. The curvature of surface 34 must correspond with the lateral curvature of the nose of the grinding wheel. Surface 35 is eccentric to surface 34.- The axes of curvature of the rough wheel truing pin and of surfaces 34 and 35 all lie in the central vertical plane of the grinding wheel, the axis of curvature of surface 35 being farther from the axis of largement 36 upon which the teeth 0f the cutter rest individually during the grinding operation. This enlargement is preferably beveled, as at 37 to provide for grinding cutters having spiral teeth, One side of the enlargement is provided with a groove or opening to receive the edge of the grinding wheel.

In grinding a cutter, it is necessary in order to obtain the required clearance angle on the teeth, to perform the grinding operation at a point below the horizontal diameter of the grinding wheel, Consequently the top of the rest by which the teeth of the cutter are supported while being ground is located the required distance below the hori-' zontal diameter of the grinding wheel. The periphery of the grinding wheel is so shaped that the edge curvature of a horizontal section through the wheel at the top of the rest will exactly correspond with the curvature of templet guide surface 34 and will lie in exact vertical alinement therewith. In other words, the center of curvature of the wheel truing guide surface must project beyond the center of curvature of the tem let guide surface a distance equal to the di erence between half the horizontal diameter of the grinding wheel and half the chord of the grinding wheel at the top of the rest. The center of curvature of the path traversed by the point of the diamond, presently to be described, in the truing-operation is inexact vertical alinement with-the-center of curvature of guide surface 35. During the grinding operation, the edge of the cutter, tooth being operated upon is in exact vertical alinement with templet guide surface 34.

64 denotes the frame of the truing device which is mounted to slide on an incline 65 on a base 66 adapted to be moved 'over the surface of the table. 67 denotes a stop block mounted to rotate on a screw stud 68 engagin the base and provided with a pluralityo f stopping surfaces 69 which are.

located at progressive distances from the axis of the screw stud and either of which is adapted to be engaged by the edge of the frame to determine the position of the frame on the incline, and consequently the height of the cutting point of the diamond above the surface of the table. The engaging edge of the frame is shown as cut away as at 71 to provide clearance for the stop block. 72 denotes the diamond which is carried by a holder 73threaded to engage a correspondingly threaded hole in the frame. The adjustment of the diamond is effected as follows. The front ofthe frame is provided with a vertical groove 76 which is adapted to receive a diamond setting rod 77. This rod comprises a part 78 which corresponds exactlyindiameter with the diameter of the portion of contact member 80 having the templet guide surface 34, and a part 79 of greater diameter, the diameter of said part 79 corresponding exactly with the diameter of rough wheel truing pin 33 and with the portion of contact member 80 having the wheel truing guide surface 35. In adjusting the diamond, part 79 of the setting rod is held firmly 1n engagement with the walls of the groove, and the diamond is positioned by turning the holder forward until the point of the diamond engages part 78 of the setting rod. The diamond holder is then looked in position by a set screw 74 engaging a plug 75 which engages the thread of the holder. The relation between the point of the diamond and the walls of the groove is now such that if the frame is placed with the walls of the groove in engagement with either rough wheel truing pin 33 or the wheel truing guide surface, and the grinding wheel is positioned by movement of the spindle head, and then the frame is oscillated about rough wheel truing pin 33 or guide surface 35, as may be, the periphery of the grinding wheel when rotated will be rounded to a contour exactlycorresponding with the curvature of said truin pin or guide surface. The dia mond settmg rod may be free, its base resting upon th table when in use, or it may be fixed in the table, as preferred.

In order to retain the vertical alinement of the operative portion of the grinding wheel and the templet guide surface, it is necessary that the grinding wheel be trued at approximately the horizontal diameter thereof, while the grinding action takes place, as already explained, below the horizontal diameter thereof. By truing the grindin wheel at approximately its horizontal iameter, l insure that a slight error in the height of the cutting point of the diamond will not make any appreciable difference in the diameter of the wheel, and will not cause any displacement of the operative portion of the wheel with rela- Laeaeee tion to the templet guide surface. In other words, it is necessary to maintain without appreciable variation the difference between half the horizontal diameter of the grinding wheel and half the chord of the grinding wheel at the operative point in its periphery. It will be obvious that without compensating means the above described relation-of the horizontal diameter of the grinding wheel and its operative point at the top of the rest would become changed in use owing to the wearing away of the grinding wheel and its consequent reduction in diameter, the effect of which would be to destroy the vertical alinement of guide surface 34 and the operative portion of the wheel. Furthermore, the cutting point of the diamond may from wear become more or less eccentric to the axis of the holder. In order to overcome these difliculties and to enable the operator to maintain the desired relation between the horizontal diameter ofthe grinding wheel and thetop of the rest, I mount the spindle head on a way upon incline 23 on the table. When it is required to compensate for wearing away of the grinding wheel and a reduction in its diameter, screw 24 is rotated by means of the hand wheel andthe spindle head is moved obliquely backward and downward as seen in Fig. 1. This places the axis of the grinding wheel nearer to the rest and also places the horizontal diameter of the grinding wheel nearer to the top of the rest, thereby compensating for the wearing away of the wheel.

In truing a grinding wheel, the truing def vic is placed in position against wheel truing surface 35, the diamond having been adjusted as described, and then the base of thetruing device is pushed under the frame successively to the several positions determined by the stopping surfaces of the stop block. This causes the cutting point of the diamond to be raised or lowered to successive positions both above and below the horizontal diameter of the grinding wheel, one of whichwill be at, or extremely close to the horizontal diameter of the wheel. Consequently, if the wheel be brought into contact with the diamond while in rotation, and the diamond is oscillated about the periphery thereof at each of the heights determined by the stopping surfaces of the stop block, the wheel will be trued to such diameter and contour of nose that the periphery at the horizontal diameter will be in vertical alinement with guide surface 35 and the periphery at the operative point, i. e. at the top of the rest, will be in vertical alinement with guide surface 34, thus insuring the reproduction on the edge of the cutter teeth of the configuration of the templet. t

It will of course be understood that my novel grinding machine is intended to grind.

to prevent wearing away of the rest. lhe

rinding wheel is placed in position by adustment of spindle head 22 and then the diamond carrying frame is placed with the walls of the oove in engagement with pin 38 and is oscillated thereon. The operation is then completed with the use of the rest. Whenever slight truing up only is required, the operation may be performed by placing the groove of the truing device in engagement with wheel truing guide surface 35 and oscillating the truing device about the guide surface as before, it being understood of course that the wheel is rotated in the usual manner. v

Having thus described my invention, 1

claim 1. Means for truing wheels: for grinding formed cutters comprising adjustable means for rotatively supporting the wheel to be trued, a frame adapted to be stably supported and slide upon a flat surface, means for guiding said frame in a fixed curvilinear path around the grinding edge of the wheel to be trued, said frame being movable toward and away from said guiding means, a horizontally adjustable truing tool mounted in said frame and having its operative edge projecting therefrom, and means for raising and lowering said frame whereby the relative vertical position of said tool may be varied.

:2. Means for truing wheels for grinding formed cutters comprising adjustable means for rotatively supporting the wheel to be trued, a frame adapted to be stably supported and slide upon a flat surface, a curved guiding element, said frame being provided with a vertical groove adapted to receive said guiding element when the frame is moved up to itwhereby said frame may be oscillated in a fixed curvilinear path around said element, a horizontally'adjustable truing tool mounted in said frame and having its operative point located in the vertical projection 0 said groove, and means for raising and lowering said frame to adjustably vary the relative vertical position of said tool. I

3. Means for truing wheels for grinding formed cutters comprising adjustable means for rotatively supporting the wheel std be trued a frame adapted to be stably supported and slide upon a flat surface, a curved guiding element, said frame beingprovided I oscillated in a fixed curvilinear having an inclined upper face,

with a vertical groove adapted to receive said guiding element when the frame is moved up to it whereby said frame may be ath around said element, a horizontally ad ustable truing tool mounted in said frame and having its operative point located in the vertical projection of said groove, and means for raising and lowering said frame, the vertical position of said tool may be varied to substantially preserve the same relative positional relationship between said tool and the grinding edge of said wheel when the latter is raised or lowered.

4. Means for truing wheels for grinding formed cutters comprising adjustable means for rotatively supporting the wheel to be trued, a base-block adapted to rest stably and slide upon a having an inclined upper face, a frame having a complementally inclined bottom adapted to rest upon said base-block and be se cured thereon in various relative positions, means for guiding said frame and block in a fixed curvilinear path around the grinding edge of the wheel said frame being movable toward and away from said guiding means, and a horizontally adjustable truing tool mounted in said frame and having its operative edge projecting therefrom.

5. Means for truin wheels for grinding formed cutters comprising adjustable means for rotatively supporting the wheel to be trued, a base-block adapted to rest stably and slide upon a flat support, said block having an inclined upper face, a. frame having a complementally inclined bottom adapted to rest upon said base-block and be secured thereon in various relative positions, a curved guiding element, said frame being movable toward and from said guiding element and provided with a vertical groove adapted to receive said guiding element whereby "said frame may be oscillated in a fixed curvilinear path around .said element, and a horizontally adjustable truing tool mounted in said frame and having its operative edge located in the vertical pr0- jection of said groove.

6. Means for truin wheels for grinding formed cutters comprising adjustable means for rotatively supporting the wheel to be trued, a base-block adapted to rest stably and slide upon a flat support, said block a frame having a complementally inclined bottom adapted to rest upon said base-block and be secured thereon in various relative positions,- an adjustable gage-sto on said base-block provided with a plura ity of bearing faces to engage the rear edges of said frame whereby said positions may be exactly predetermined, means for guiding said frame in a fixed curvilinear path around the grinding edge of the wheel,;anda horizontally whereby fiat support, said block' adjustable truing tool mounted in said frame and having its operative edge projecting therefrom.

7. Means for truing wheels for grinding formed cutters comprlsing a base having an incline, a frame slidable on the incline, a truing tool adjustably mounted in said frame and having its operative edge projecting therefrom, and a rotatable stop block having a plurality of stopping surfaces at progressive distances from the axis of the block, said frame being adapted to engage the several stopping surfaces to determine the height of the truing tool, the said base and frame being freely movable along a flat surface and adapted at the working side to engage and work in a curvilinear path around a fixed guide.

8. Means for truing wheels for grinding formed cutters comprising, an incline, a frame slidable thereon for the purpose set forth, said frame being provided with a groove adapted to receive a curved guiding element whereby said frame may be oscillated in a fixed horizontal path around said element, and a truing tool adjustably mounted on the frame and positioned horizontally by said guiding element and vertically by said incline.

9. The combination, with adjustable means for rotatively supporting a wheel for grinding formed cutters, and a rest for the cutter to be ground located below the horizontal plane through the axis of the wheel,

of a truing tool, means for supporting said tool for movement horizontallyin said axial plane, means for guiding said tool-supporting means around the grinding edge of said wheel, and adjusting devices for the tool carrying frame and the wheel supporting means, for insuring maintenance of the desired configurative relation between the trued edge of the wheel in said horizontal axial plane and the grinding edge thereof in the horizontal plane at the top of said rest as the diameter of said wheel is gradually reduced.

10. The combination, with adjustable means for rotatively supporting a wheel for grinding formed cutters, and a rest for the cutter to be ground located below the horizontal plane through the axis of the wheel, of a truing tool, means for supporting said tool for movement horizontally in said axial plane, said rest including a curved element and said tool-supporting means being provided with a vertical groove adapted to receive said element, whereby said supporting means may be os'cillated ina fixed curvilinear path around the grinding edge of said wheel, and adjusting devices for the tool carrying frame and the wheel su porting means for insuring maintenance 0 the desired configurative relation between the trued edge of the wheel in said horizontal masses axial plane and the grinding edge thereof in the horizontal plane at the top of said rest as the diameter of said wheel is gradually reduced.

11. The combination, with adjustable means for rotatively supporting a wheel for grinding formed cutters, an inclined base upon which said wheel supporting means is slidable, and means for moving said supporting means gradationally up and down said inclined base, ofaframe stably supported and slidable upon a fiat surface, means for guiding said frame in a fixed curvilinear path around the grinding edge of the wheel, said frame being movable into and out of engagement with said guiding means, a horizontally adjustable truing tool mounted in said frame and having its operative edge projecting therefrom, and means for varying the vertical position of said tool.

12. The combination, with adjustable means for rotatively supporting a wheel for grinding formed cutters, an inclined base upon which said wheel supporting means is slidable, and means for moving said supporting means gradationally up and down said inclined base, of a frame stably supported and slidable upon a flat surface, a curved guiding element, said frame being movable toward and from said curved guiding element and provided with a vertical groove adapted to receive said guiding element whereby said frame may be oscillated in a fixed curvilinear path around said element, a horizontally adjustable truing tool mounted in said frame and having its operative point located in the vertical projection of said groove, and means for varying the relative vertical position of said tool.

13. The combination, with ad ustable means for rotatively supporting a wheel for grinding formed cutters, an inclined base upon which said wheel supporting means is slidable, and means for moving said supporting means gradationally up and down said inclined base, of a base-block adapted to rest stably and slide upon a fiat support, said block having an inclined upper face, a frame having a complementally inclined bottom adapted to rest upon said block and be se-' cured thereon in various relative positions of adjustment, means for guiding said frame and block in a fixed curvilinear path around the grinding edge of said wheel, said frame and block being movable upon the flat support toward and from said guidin means, and a horizontally adjustable truing tool mounted in said frame and having its operative edge projecting therefrom.

14. The combination, with adjustable means for rotatively supporting a wheel for grinding formed cutters, an inclined base upon which said wheel supporting means is slidable, and means for moving said supporting means gradationally up and down said inclined base, of a base-block adapted to rest stably and slide upon a fiat support, said block having an inclined upper face, a frame having a complemen'tally inclined bottom adapted to rest upon said block and be secured thereon in various relative positions of adjustment, a curved guiding element, said frame being movable along said flat support toward and from said curved guiding ele- 10 ment and provided with a vertical groove adapted to receive said element whereby said frame may be oscillated in a fixed curvilinear path around said element, and a horizontally adjustable truing tool mounted in said frame and having its operative edge located in the vertical projection of said groove.

In testimony whereof I aflix my signature.

WILLIAM O. BARNES. 

